Operating Range

Operating range is one of the most significant limitations facing the current fleet of heritage locomotives that operate on UK main line.  In a few cases, their range is increased by the addition of an extra water tank or tender, but most are limited to the capacity of tenders that were designed in the age of steam when water troughs were available for on-the-run refilling.  This often allows them a range of little more than 200 km.The provision of a large (80 tonne) tender behind the locomotive allows large quantities of fuel and water to be carried, with an estimated total of just over 53 tonnes (refer FDC 1.3 line 12).  Wardale has based his estimates of the 5AT’s operating range on dividing this capacity into 7 tonnes of gas-oil and 46.3 tonnes (m³) of water.

From his estimates of the locomotive’s fuel and water consumption at maximum drawbar power, Wardale estimates its operating range based on fuel supply to be 565 km (351 miles), and on water supply to be 367km (228 miles) under continuous operation at 113 km/h (70 mph) when delivering 1882 kW (2521 hp) at the drawbar.

Conservatively assuming that under “average representative service conditions” the fuel and water consumption would be 60% of those pertaining at maximum drawbar power, he deduces that the locomotive should have a range of 942 km (585 miles) from its fuel supply, and 612 km (381 miles) from its water supply, or more than double that of a regular heritage locomotive.  However taking account of the need to allow for a “reserve” water capacity, a practical range of 500 km (310 miles) is suggested for route planning purposes.  This figure will, of course, be subject to review based on experience gained when running the locomotive.